1. Field of the Invention
The present invention relates to an occupant detecting system for-detecting the presence or absence and the physique or attitude of an occupant sitting on a seat of an automobile.
2. Description of the Related Art
An air bag device and a seat belt device for holding back an occupant sitting on a passenger""s seat upon a collision of a vehicle are designed on the basis of the physique of an adult. The air bag device and the seat belt device do not necessarily function effectively for a small child in some cases. For this reason, when a child is sitting on the passenger""s seat, it is desirable that a warning is given to move the child to a rear seat, or the sudden deployment of an air bag is suppressed. Therefore, an occupant detecting system has been proposed in Japanese Patent Application Laid-open No. 52129127, which is designed to detect the presence or absence and the physique of an occupant sitting on a passenger""s seat by providing a plurality of switches which are operated depending on the weight of the occupant sitting on the passenger""s seat.
The above conventional occupant detecting system is adapted to detect the presence or absence of the occupant by a switch provided in a seat cushion and to detect the physique of the occupant, i.e., whether an adult or a child, by a switch provided in a seat back and a switch provided in a head rest. However, the above conventional occupant detecting system suffers from a problem that a detection error is liable to be produced due to a variation in hardness of a seat skin member caused by a variation in temperature, a variation in sitting attitude of an occupant, a variation in reclining angle of the seat back and the like, because each of the switches is operated depending on the weight of the occupant.
A side air bag device is conventionally known, for example, from Japanese Patent Application Laid-open No.6-64491, which is adapted to be deployed along an inner surface of a door from a side of a seat back upon a collision of a vehicle to protect a side of an occupant.
The above side air bag device suffers from a problem that when a child sitting on a passenger""s seat has fallen asleep to lean toward a door, the head of the child having a short sitting height covers the front of the side air bag device accommodated in a side of a seat back and hence, a side air bag cannot be deployed effectively. Therefore, it can be conceived that the physique and attitude of an occupant sitting on the passenger""s seat is detected by an imaging means, such as a camera, and when a child is in a sleeping attitude in which he or she is leaning against the door, the operation of the side air bag device is prohibited.
In this case, however, there is encountered a problem that an expensive camera is required for the detection of the occupant by the imaging means and for this reason, the cost is not only increased, but also the precise detection is difficult because it is governed by the reclining angle of the seat back and the brightness within a vehicle compartment.
It can be also conceived that a sheet-shaped antenna electrode is embedded between a pad of the seat back and a trim cover covering the surface of the pad for detecting the sitting attitude and physique of an occupant sitting on the passenger""s seat, and when a child is in a sleeping attitude in which he or she is leaning against the door, the operation of the side air bag device is prohibited. In this case, if the antenna electrode is attached directly to the surface of the pad of the seat back, the antenna electrode can be mounted at a correct position to avoid a reduction in detection accuracy by previously integrally formed irregularities serving as a mark indicating the mounted position of the antenna electrode, when the pad is molded. In fact, however, a sheet-shaped wadding is adhered to the surface of the pad to improve the touch of the seat upon sitting of an occupant, and the antenna electrode is superposed on, and adhered to, the surface of the wadding. Moreover, the wadding is made by cutting a ready-made sheet having a large area into a predetermined size and for this reason, the provision of the irregularities as the mark indicating the mounted position of the antenna electrode is undesirable, because it is a factor for an increase in cost.
When the sheet-shaped antenna electrode is embedded in the seat back, there is a possibility that the cushion property of the seat back may be injured by the antenna electrode, thereby giving an uncomfortable feeling to an occupant sitting on the seat.
Accordingly, the present invention has been made in view of the above and it is a first object of the present invention to provide an occupant detecting system capable of reliably detecting the presence or absence and the physique of an occupant sitting on a seat of an automobile.
It is a second object of the present invention to ensure that the operation of the side air bag device is reliably prohibited, when an occupant sitting on a seat is in a sleeping attitude in which he or she is leaning against a door.
It is a third object of the present invention to ensure that, when an antenna electrode is fixed to the surface of a pad of the seat through a wadding, the antenna electrode can be positioned easily and reliably without provision of a special mark.
To achieve the above first object, according to a first aspect and feature of the present invention, there is provided an occupant detecting system comprising a plurality of electrode fabrics embedded in a seat back of a seat in an automobile, an electric field generating means for generating an electric field around the electrode fabrics, a human body approach detecting means for detecting the approach of a human body of the electrode fabrics based on electric current flowing from the electric field generating means to each of the electrode fabrics, and a determining means for determining the presence or absence, and the physique, of an occupant sitting on the seat by comparing a combined pattern of those outputs from the human body approach detecting means which correspond to the electrode fabrics with a previously stored pattern.
With the above arrangement, when the occupant sits on the seat, the human body having a high dielectric constant as compared with that of air approaches the plurality of electrode fabrics embedded in the seat back and hence, electric current flowing from the electric field generating means to each of the electrode fabrics is increased. When the electric current flowing to the electric fabrics is increased, the human body approach detecting means detects the approach of the human body to the electric fabrics based on such electric current. The determining means compares the combined pattern of the outputs from the human body approach detecting means with the previously stored patterns, determines whether the occupant is sitting on the seat and determines the physique of the occupant sitting on the seat.
Since the presence and absence and the physique of the occupant sitting on the seat are determined based on the approach of the human body, which is a dielectric to the plurality of electrode fabrics, it is possible to carry out the precise determination irrespective of a variation in hardness of a seat skin member caused by a variation in temperature, a variation in sitting attitude of the occupant, a variation in reclining angle of the seat back, and the like.
To achieve the second object, according to a second aspect and feature of the present invention, there is provided an occupant detecting system comprising an electric fabric embedded in a side of a seat back of a seat in an automobile, an electric field generating means for generating an electric field around the electrode fabric, a human body approach detecting means for detecting the approach of a human body to the electrode fabric based on electric current flowing from the electric field generating means to the electrode fabric, and a determining means for determining whether the body of an occupant sitting on the seat is leaning sideways, based on an output from the human body approach detecting means.
With the above arrangement, when the body of an occupant sitting on the seat leans sideways, the body of the occupant having a high dielectric constant as compared with that of air approaches the electrode fabric embedded in the side of the seat back and hence, the electric current flowing from the electric field generating means to the electrode fabric is increased. As a result, the human body approach detecting means detects the approach of the occupant body to the electrode fabric based on the electric current, and the determining means determines whether the body of the occupant is leaning sideways, based on the result of such detection.
To achieve the second object, according to a third aspect and feature of the present invention, there is provided an occupant detecting system comprising a plurality of first electrode fabrics embedded in a central portion of a seat back of a seat in an automobile, at least one second electrode fabric embedded in a side of the seat back of the seat, an electric field generating means for generating an electric field around the first and second electrode fabrics, a human body approach detecting means for detecting the approach of a human body to the first and second electrode fabrics, based on electric current flowing from the electric field generating means to the first and second electrode fabrics, a first determining means for determining whether a sitting height of an occupant sitting on the seat is equal to, or smaller than, a reference value by comparing a combined pattern of outputs from the human body approach detecting means which correspond to the first electrode fabrics with a previously stored pattern, a second determining means for determining whether the body of an occupant sitting on the seat is leaning sideways, based on an output from the human body approach detecting means which corresponds to the second electrode fabric, and a signal outputting means for outputting a signal indicative of a command to prohibit the deployment of a side air bag device provided in the side of the seat back, when the first determining means determines that the sitting height of the occupant sitting on the seat is equal to, or smaller than, the reference value, and the second determining means determines that the body of the occupant is leaning sideways.
With the above arrangement, when the occupant sits on the seat, the body of the occupant having a high dielectric constant as compared with that of air approaches the first and second electrode fabrics embedded in the seat back and hence, the electric current flowing from the electric field generating means to the electric fabrics is increased. When the electric current flowing to the electrode fabrics is increased, the human body approach detecting means detects the approach of the human body to the electrode fabrics, based on such electric current.
The first determining means compares the combined pattern of those outputs from the human body approach detecting means which correspond to the plurality of first electrode fabrics with the previously stored pattern, and determines whether the sitting height of the occupant sitting on the seat is equal to, or smaller than, the reference value. The second determining means determines whether the body of the occupant sitting on the seat is leaning sideways, based on those outputs from the human body approach detecting means which correspond to the plurality of second electrode fabrics. The signal outputting means outputs the signal indicative of the command to prohibit the deployment of the air bag device by determining that a small occupant is sitting on the seat in a sleeping attitude, when the sitting height of the occupant is equal to, or smaller than, the reference value and the body of the occupant is leaning sideways.
To achieve the second object, according to a fourth aspect and feature of the present invention, there is provided an occupant detecting system comprising a weight detecting means embedded in a seat cushion of a seat in an automobile, at least one electrode fabric embedded in a side of a seat back of the seat, an electric field generating means for generating an electric field around the electrode fabric, a human body approach detecting means for detecting the approach of a human body to the electrode fabric, based on electric current flowing from the electric field generating means to the electrode fabric, a first determining means for determining whether the weight of an occupant sitting on the seat is equal to, or smaller than, a reference value, based on an output from the weight detecting means, a second determining means for determining whether the body of the occupant sitting on the seat is leaning sideways, based on an output from the human body approach detecting means, and a signal outputting means for outputting a signal indicative of a command to prohibit the deployment of a side air bag device provided in the side of the seat back, when the first determining means determines that the weight of the occupant sitting on the seat is equal to or smaller than the reference value and the second determining means determines that the body of the occupant is leaning sideways.
With the above arrangement, when the occupant sits on the seat, the weight detecting means embedded in the seat cushion detects the weight of the occupant, and the first determining means determines whether the detected weight is equal to, or smaller than, the predetermined value. When the occupant sits on the seat, the electric current flowing from the electric field generating means to the electrode fabric is increased, because the human body having a high dielectric constant as compared with that of air approaches the electrode fabric embedded in the side of the seat back. When the electric current flowing to the electrode fabric is increased, the human body approach detecting means detects the approach of the human body to the electrode fabric, based on the electric current. The second determining means determines whether the body of the occupant on the seat is leaning sideways, based on the output from the human body approach detecting means.
When the first determining means determines that the weight of the occupant is equal to, or smaller than, the reference value and the second determining means determines that the body of the occupant on the seat is leaning sideways, based on the output from the human body approach detecting means, the signal outputting means outputs the signal indicative of the command to prohibit the deployment of the side air bag device on the basis of the determination of a small occupant sitting in a sleeping attitude.
The physique of the occupant is determined based on the weight of the occupant, and the leaning of the body of the occupant is determined based on the approach of the human body which is a dielectric. Therefore, it is possible to reliably detect a state in which a small occupant having a short sitting height is sitting on the seat in a sleeping attitude, thereby prohibiting the deployment of the side air bag device.
To achieve the third object, according to a fifth aspect and feature of the present invention, there is provided an occupant detecting system comprising a sheet-shaped antenna electrode fixed to a surface of a pad of a seat back through a wadding to detect the sitting attitude and physique of an occupant, wherein the antenna electrode is positioned on the pad by conforming at least a portion of the profile of the antenna electrode to the profile of the pad.
With the above arrangement, when the sheet-shaped antenna electrode is fixed to the surface of the pad of seat back through the wadding, the antenna electrode can be positioned easily and precisely without provision of a special mark by conforming at least a portion of the profile of the antenna electrode to the profile of the pad, thereby enhancing the accuracy of detection of the sitting attitude and physique of the occupant.
To achieve the fourth object, according to a sixth aspect and feature of the present invention, there is provided an occupant detecting system comprising a sheet-shaped antenna electrode formed of an electrode fabric laminated on a base fabric, the antenna electrode being fixed to a surface of a seat back, wherein the electrode fabric has an opening made therein.
With the above arrangement, the flexibility of the antenna electrode is increased by virtue of the opening made on the electrode fabric and hence, the conformation of the antenna electrode to the seat is improved, leading to an enhanced sitting feeling of an occupant.